The present invention relates to a clipless pedal device with an attachment arrangement for securing a first securing arrangement provided on the pedal with a second securing arrangement fixed under the sole of the cycling shoe.
Many clipless pedal attachment systems are known.
The single-sided attachment systems of patent FR 2 442 175 comprise a fixed attachment snout situated at the front of the pedal, and a moving claw situated at the rear of said pedal, this claw being returned by an elastic member into a position in which it locks a cleat fixed under the shoe.
Such a pedal is also known from publication WO2005/016736 which discloses the use of an elastic return member consisting of two helical springs that are compressed as the cleat is engaged or disengaged. Another example of an elastic return member that is stressed in compression is given in publication US2003/066385. This elastic member, which is housed in an attachment cleat, also comprises helical springs which are compressed by the action of pushing against a part that projects as the cleat is engaged.
More recently, with the advent of mountain biking (MTB), double-sided attachment clipless pedals have appeared, in which pedals the retaining means have two opposite attachment sides one on each side of the pedal body.
By using a double-sided attachment clipless pedal device, the cyclist does not have to find the side of the pedal that is provided with the cleat retaining means, can clip back in quickly and remain balanced while continuing to look straight ahead.
A double-sided attachment pedal is known from publication EP0557735. This pedal comprises an elastic return member consisting of a helical spring which, as a cleat is engaged on or disengaged from the pedal, is compressed and then relaxes to bring the moving claw back into its initial position. Another example of a double-sided attachment pedal comprising a compressively stressed elastic return member is given in U.S. Pat. No. 6,324,941. In that document, the elastic means consists of compression springs arranged on each side of the axis of the pedal.
Because of the mud involved in this kind of pursuit, and because of the trouble it causes in the operation of pedal attachment systems, steps have been taken to make this mud easier to remove, by hollowing out the pedal bodies as far as possible, and to improve attachment using members that are as slender as possible, particularly attachment members in the form of loops or bows made of metal wire.
U.S. Pat. No. 6,205,885 describes a clipless pedal provided with such bows, centered on the axis of the pedal, and with four sides for attaching the cleat to the pedal body, each attachment side being defined between a pivoting bow and a fixed bow.
Patent FR 2 861 362 describes a clipless pedal provided with such bows which are eccentric and arranged at the periphery of the pedal axis.
These bows or claws are most often returned to the locking position using springs made of metal wire under bending stress.
A clipless pedal, of reduced weight and with a low number of component parts, in which attachment is onto two bows which themselves act as bending springs, is described in patent EP 0296 898.
Another clipless pedal, of reduced weight with a low number of component parts, in which attachment is to bows which themselves act as bending springs, is described in patent EP 1 780 113. The attachment bows are all independent of one another. The ends of these attachment bows are offset from one another to create inset and to stress the bow in bending along bending axes that are offset from one another.
This kind of MTB clipless pedal is manufactured under the Quartz trade name by the company under French Law LOOK CYCLES and is presented on the website accessible via the link: http://www.lookcycle.com/quartz/ or is presented in video form on the website accessible via the link: http://www.youtube.com/watch?v=6brlmKvgydE&feature=related
This pedal manufactured under the QUARTZ trade name may, however, suffer a risk of lack of rigidity of the steel wire that acts as the return spring and serves to attach the cleat to the pedal body. This risk of lack of rigidity may lead to unwanted unclippings.
This QUARTZ pedal may also suffer a risk of stress concentration in the steel wire that acts as the return spring and serves to attach the cleat to the pedal body, particularly in the cranked portions thereof. The steel wire that acts as the return spring and serves to attach the cleat to the pedal body ages more quickly in the regions of stress concentration and becomes less and less rigid.